Many commercially available food products, including sterile-treated fruit juice, wine, UHT milk, tomato puree etc., are packed in packages which are manufactured from a previously sterilised or sterile-treated packaging material. A typical example of this kind of package is the parallelepipedal packaging container for liquid or pourable food products, which is known by the name Tetra Brik Aseptic (Registered Trade Mark), which is manufactured by folding and sealing of a web-shaped laminated packaging material. The laminated packaging material comprises layers of fibrous material such as paper, which are coated on either side with a thermoplastic material such as polyethylene. On the side of the laminated packaging material which is destined to be in contact with the food contents of the package, there is also a layer of barrier material, such as e.g., aluminum foil, which is also coated with a thermoplastic layer.
In order to manufacture parallepipedal packaging containers of this type, filling or packaging machines are fed with laminated packaging material in web form. The packaging material web is sterilised in the packaging machine by the application of a chemical sterilization agent such as e.g., hydrogen peroxide solution. Upon completion of sterilization, the sterilization agent is removed from the surfaces of the packaging material, for example, it may be vaporised by heating. The thus sterilised packaging material web is retained in a closed sterile space and is folded and longitudinally sealed to form a tube. The tube is filled with sterile-treated food product and is transversely sealed and cut into pillow-shaped, filled and sealed packaging containers, which are then mechanically folded to form a parallepipedal package.
An example of this type of packaging machine is the TBA19 aseptic filling machine, manufactured by Tetra Brik Packaging Systems, Via Delfini 1, Modena, Italy.
In order to open this type of package, several solutions have been proposed. One solution consisted in the provision of a line of perforations, partially penetrating the outer layers of the laminated packaging material but leaving the internal barrier layer or layers intact, and extending across the comer zone of a flap of the package. By raising the flap and cutting or tearing along the perforations, the package was opened, and the contents could be poured from the package. Such solutions are described in U.S. Pat. No. 4,655,387 and in U.S. Pat. No. 4,410,128.
However, since packages of this type could not be reclosed, they had to be handled in a careful manner to avoid spillage, until all of the contents were used.
In order to overcome this inconvenience, various types of reclosable opening devices have been proposed. One such solution consisted in the provision of an outlet opening formed in the packaging material laminate and a pull-tab applied over the opening in the filling or packaging machine, with a frame-like pouring device having a reclosable lid connected to the outside of the filled and formed package over the pull-tab. In order to access the contents of the package, a user must first open the lid, and then remove the pull-tab. Once the desired quantity of contents has been removed from the package, the lid can be reclosed.
While this solution is extremely advantageous from many standpoints, it has been found to be susceptible to improvement. Specifically, it would be desirable to have an opening device which permits a user to open the above-described type of package in a single operation, and thereafter provide the possibility of package reclosure with improved liquid-tightness.
Packages of the so-called gable-top type are also known, which are usually formed from a packaging material blank on a mandrel and are particularly suitable for pasteurised food products. By pulling apart the ends of a pair of opposite inclined walls of a gable top package, a portion of the uppermost sealed ridge or fin of the package is ruptured, and a spout-like portion can be opened outwards to enable the contents to be poured from the package. However, also this opening arrangement has the disadvantage that it cannot be securely reclosed, and therefore also gable-top packages provided with this type of opening arrangement have to be handled in a careful manner to avoid spillage, until all of the contents are used.
Laid-open Japanese Patent No. 63-149818 describes an opening device used for packages of the gable-top type, which are usually formed from a packaging material blank on a mandrel and are particularly suitable for pasteurised food products. The opening device has a frame affixed to one of the two inclined walls of the gable-top package and bearing two upright semi-circular walls. A lever having a matching semi-circular configuration is journalled between the walls for rotation about an axis passing substantially through the centers of the planar bases of the semi-circular walls, parallel and adjacent to the surface of the package. The lower portion of the lever facing the package has teeth for rupturing the packaging material, and a grip-tab, whereby a user can open the package by rotating the lever in one direction, and reclose the package by rotating the lever in the opposite direction.
However, this kind of opening device requires the application of significant force in order to drive the teeth through the packaging material. This may lead to inadvertent spillage of the contents of the package. Furthermore, the excessive force exerted on the points whereat the lever is journalled to the walls, may cause damage to or even breakage of the device. Moreover, although the device can be reclosed after opening, the reclosure is not liquid-tight, whereby spillage may occur in the event that a reclosed container is accidentally knocked over.
A screw cap provides a better degree of liquid-tightness when reclosed, but when using a screw cap on an aseptic package of the above-described type, some provision has to be made for rupturing the barrier layer of the container at the time of opening, so as to maintain the aseptic quality of the package, right up to the moment when the package is opened for consumption of the product contained therein.
Known from laid-open Japanese Patent Application No. 63-156928 is a three-piece opening device consisting of a frame having an externally threaded portion, a screw-cap which can be screwed onto the frame, and a sleeve located in a tubular portion of the frame and having a lower toothed edge which, when actuated by screwing the cap onto the frame, perforates the laminated packaging material of a container. A rupturable collar is affixed to the periphery of the screw cap in a known manner as a tamper evidence. If the collar of a package on a store shelf is ruptured or severed from the screw cap, this indicates to a consumer that the package has been previously opened and should not be purchased because the contents of the package will no longer be in an aseptic state. However, this device is structurally complicated, and if a cap has been unscrewed and replaced, the tamper evidence can easily be overlooked by a customer in a hurry or by anyone with less than perfect eyesight, since the rupturable plastic portions connecting the collar to the screw cap are only about one millimeter long.
Laid-open Japanese Patent Application No. 64-2727 describes an opening device for the above-mentioned gable-top type of package. This latter device has a frame defining a tubular portion, a sleeve arranged slideably within the tubular portion and connected to the frame by a collapsible bellows, and a cap hinged to the frame and overlying the open uppermost end of the sleeve in a closed position. A user has to apply pressure on the cap, which is transferred to the sleeve, thereby collapsing the bellows. The lower end of the sleeve punctures the packaging material of the container and the reclosable cap can be opened to pour the contents.
However, the cap can be knocked during handling and transportation, thereby inadvertently collapsing the bellows and causing the sleeve to puncture is the underlying packaging material, and thus, the contents of the package will no longer be in an aseptic state. However, if the collapsed bellows is extended to its original position, a consumer is unaware that a previous opening has occurred and could inadvertently purchase such a package and consume its contents, with inherent health risks.
Also known from Japanese utility model patent No. JP-62-90320 is an opening device having a screw cap engaging the screw threads of a spout. The spout is affixed to a package, and a cutting member is provided in the spout. The cutting member can be directly pushed, by exerting pressure thereon with the finger, through the packaging material constituting the package. A mechanism is provided for locking the cutting member in an opened position within the spout, whereby to avoid interference during pouring of the contents of the package. However, the fact that the cutting member is pushed with the finger, is a source of possible contamination of the contents during the opening operation. Furthermore, there is no effective tamper evidence to alert a consumer when a package on the shelf of a store, has been opened and the cap replaced, and thus, the contents of the package will no longer be in an aseptic state. Therefore, a consumer could be unaware that a previous opening has occurred and could inadvertently purchase such a package and consume its contents, with inherent health risks. Furthermore, such type of opening device is inconvenient to use, since it requires a first operation to access the cutter member, and then a second operation to force the cutter member through the packaging material constituting the package.
Laid-open Japanese patent application No. 63-202653 discloses a collar fixable to a package and having a cutting member hingedly connected thereto, for cutting the packaging material of a package to be opened. A spout having a snap-fitting cover or cap hinged thereto, is rotatably mounted on the collar. A cam is supported on the spout and acts on the cutting member when rotating the spout with respect to the collar, thereby forcing the cutting member into the packaging material. causing the sleeve to puncture the underlying packaging material. However, if the spout is rotated with respect to the collar before the package is sold, the contents of the package will no longer be in an aseptic state, and a consumer could inadvertently purchase such a package and consume its contents. This obviously presents a health risk.